Shifting balance of thermokarst lake ice regimes across the Arctic Coastal Plain of northern Alaska

• Published in: Geophysical research letters Vol. 39; no. 16
• Main Authors: Arp, C. D., Jones, B. M., Lu, Z., Whitman, M. S.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 28-08-2012; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Aquatic habitats; Arctic Coastal Plain; Climate change; Coastal plains; Cryosphere; Earth; Earth sciences; Earth, ocean, space; Exact sciences and technology; Floating ice; Ice; Lake classification; Lake ice; Lakes; Permafrost; Radar; thermokarst lakes; Water supply; Alaska; polar regions; Northern Alaska; United States; Arctic Coastal Plain; Arctic region; landscapes; thawing; trend-surface analysis; habitat; thermokarst; Time series; Thermal energy storage; taliks; water supply; classification; North America; Floating ice; Thinning; balance; Winter; permafrost; Radar observation; Radar imaging; heat storage; Polar region; lakes; soils; radar methods; Synthetic aperture radar
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2012GL052518

The balance of thermokarst lakes with bedfast‐ and floating‐ice regimes across Arctic lowlands regulates heat storage, permafrost thaw, winter‐water supply, and over‐wintering aquatic habitat. Using a time‐series of late‐winter synthetic aperture radar (SAR) imagery to distinguish lake ice regimes in two regions of the Arctic Coastal Plain of northern Alaska from 2003–2011, we found that 18% of the lakes had intermittent ice regimes, varying between bedfast‐ice and floating‐ice conditions. Comparing this dataset with a radar‐based lake classification from 1980 showed that 16% of the bedfast‐ice lakes had shifted to floating‐ice regimes. A simulated lake ice thinning trend of 1.5 cm/yr since 1978 is believed to be the primary factor driving this form of lake change. The most profound impacts of this regime shift in Arctic lakes may be an increase in the landscape‐scale thermal offset created by additional lake heat storage and its role in talik development in otherwise continuous permafrost as well as increases in over‐winter aquatic habitat and winter‐water supply.
Key Points
Thermokarst lake ice regimes vary with ice thickness and water balance
Thinning ice trend explains a shift from bedfast‐ to floating‐ice lakes
Floating‐ice lakes enhance heat storage, permafrost thaw, and winter habitat